Findings from an Experiment on Flow Direction of Business Process Models

A core aspect of diagrammatic process modeling is the visualization of the logical and temporal order in which tasks are to be performed in a process. While conventions and guidelines exist that promote modeling processes from left-to-right or from top-to-bottom, no empirically validated design rationale can be provided for this choice so far. Therefore, this paper seeks to determine whether some flow directions are better than others from a cognitive point of view. We present the results of a controlled pilot experiment comparing the effects of four flow directions (left-to-right, right-to-left, top-to-bottom, bottom-to-top) on process model comprehension with a small sample size of 44 participants. Although there is a variety of theoretical arguments which support the use of a left-to-right flow direction as convention for process models, the preliminary empirical results of the pilot experiment were less clear-cut and showed that model readers also adapted well to uncommon reading directions.